In a system where power has been conventionally generated manually, such as by rotating a handle or the like, a speed for rotating the handle is differentiated depending on a person or frequently varied so that a stable voltage is hardly obtained. It is necessary to mount a battery onto such a system so as to obtain a constant voltage, however when the battery is consumed, it need be replaced with another battery, and the used battery is wasted, resulting in fear of environmental pollution. Accordingly, employment of such a system raises a problem. As a result, there is proposed another system wherein a mechanical energy is accumulated in a spring and force of the mechanical energy is utilized. This is exemplified by a talking guide unit as disclosed in JP 2003-424032 by an applicant same as the applicant of the present invention.
FIG. 5 shows a conventional system provided with a power generation device 52 for utilizing force accumulated as a mechanical energy generated by rotating a handle 50, and a recording reproduction system 54 which is operated by the power generated by the power generation device 52. In this system, a winding-down drum 58 on which a spring 56 is wound up and a winding-up drum 60 coaxially provided onto a shaft of the handle 50 are provided so as to accumulate the mechanical energy wherein the winding down drum 58 is arranged in parallel with the winding-up drum 60, and also a power generator 66 is coaxially provided onto the shaft of the handle 50 via a clutch 64.